Engine starter gearing



1940- E. E. BALDWIN 2,226,544

ENGINE STARTER GEARING Filed NOV. 26, 1958 2 Sheets-Sheet l INVENTOR.

five/261% 8. Baldwin wanes BY A TOR Dec. 31, 1940. wm 2,226,544

ENGINE STARTER GEARING Filed Nov. 26, 1938 2 Sheets-Sheet 2 a'raeoaaah INVENTOR. Milne/.95: M 6. Baldwin BY V Patented Dec. 31, 1940 PATENT OFFICE.

ENGINE sraarna onaanvo Everett E. Baldwin, Elmira, N. Y., assignor to Bendix Aviation Corporation, South Bend, Ind..-

a corporation of Delaware Application November 2c. 1938, Serial No. 242,545

4 Claims.

. The present invention relates to enginestarter gearing and more particularly to a starter drive incorporating an elastic element which is placed under tension by the transmission of starting 5 torque.

A divisional application covering more particularly the structure describedin Figs. 4 to 8 hereof was flied on October 1, 1940, and given Serial Number 359,259.

Theincreasing strictness of space limitations with respect to automotive engine auxiliaries has emphasized the desirability of reducing the size, and particularly the overall length of starter drives without affecting their torque capacity or 15 operating characteristics. Various forms of starting devices utilizing yielding driving members of elastically deformable material such as rubber undercompression has been suggested.

It has been found, however, that-such members go are subject to abrasion by rubbing on the walls of their containers, causing disintegration of the members and sticking of the drives due to the accumulation of rubber particles'on the working surfaces. Moreover, when the yielding member 5 is compressed, its end portions become wedged in their seats so as to interfere with the defamation and displacement thereof so that when the drive is under load, the elasticity of the yielding member is confined substantially to its central portions, and the member is not uniformly stressed throughout its length.

The perfection of methods for bonding rubber and rubber substitutes to metal has permitted the use of such materials in situations in which 35 they have not hitherto been available, and it is now proposed to utilize this advanced technology in producing a starter drive incorporating both dimensional and operative improvements.

It is an object of the present invention to provides. novel engine starter drive which is small and compact in comparison to earlier types of drives having equal torque capacity.

It is another object to provide such a device which has improved operating characteristics particularly in respect to the yielding driving connection.

It is a further object to provide such a device which is efficient and reliable in operation while being simple and economical in construction.

0 It is another object to provide such a device incorporating a member of elastically deformable material which is placed under tension when torque is transmitted through the drive.

i It is another object to provide such a device 55 in which the elastic member is subjected to both tension and torsion during the cranking operation.

- Further objects and advantages-will be apparent from the following description taken in connection with the accompanying drawings in 5 which:

Fig. 1 is a side elevation partly in section of a starter drive embodying a preferred form of the invention, showing the partsin idle or disengaged position;

Fig. 2 is an end elevation of the same;

Fig. 3 is a substantially mid-sectional view of the structure illustrated in Fig. 1, showing the parts in operative position and showing an optional form of reentry device for the pinion memher;

Fig. 4 is a view similar to Fig. 1 of a second embodiment of the invention; I

Fig. 5 is asection taken substantially on the line 5-5 of Fig. 4;

Fig. 6 is a side elevation partly in section of a third embodiment of the invention showing the parts in idle position;

. Fig. 7 is an end view thereof; and

Fig. 8 is a view similar to Fig. 6, showing the 5 parts in driving position. v

In Fig. 1 of the drawings there is illustrated a power shaft I which may be the extended armature shaft of the starting motor, not shown. A flange or disc member 2 having a flat radial flange 3 is flxed to the power shaft by suitable means such as a pin 4 retained by an elastic ring 5 seated in a peripheral groove in the pin and flange member. A combined pinion and screw shaft member 6 is slidably journalled on 3 the power shaft I for movement into and out of engagement with a member such as a flywheel ring gear I of an engine to be started.

The member 6 comprises a pinion portion 8 adapted to engage the flywheel gear I and a screw-threaded cylindrical portion 9 extending toward the flange member 2. The member 6 is normally maintained by an anti-drift spring H in its idle position as shown, this position being defined by suitable means such as a stop member 5 I2 located on the power shaft l by means of a set screw 14.

A barrel member I5 is arranged to surround and partially enclose the flange member 2, and is provided with a radially inwardly extending flange it, the inner periphery of which normally rests on a smooth portion ll on the end of the screw shaft 9. The flange I6 is internally threaded as indicated at l8 to engage the threads of the screw shaft 9 upon relative rotation thereof.

cated within the barrel member l8 and has its,

ends bonded in any suitable manner to the flanges 3 and I8 as indicated at 2| and 22 respectively whereby separation and relative rotation of these flanges and accordingly of the flange member 2 and barrel I5 are yieldingly opposed by the transmission member.

The screw-shaft 8 is so dimensioned that when the pinion 8 is in full operative engagement with the flywheel gear I, the end 23 of the screw shaft comes into abutting relation with the flange 3 of the member 2 whereby the operative position of the pinion on the power shaft is defined. A thrust washer 24 is preferably interposed between the screw shaft and flange member.

The extension of the transmission member 3 is preferably limited by positive means such as a thrust ring 25 located in the barrel member at its open end, in position to engage the flange 3 and prevent its withdrawal from the barrel member.

In the operation of this embodiment of the invention, starting with the parts in the positions illustrated in Fig. 1, rotation of the power shaft in the direction of the arrow causes rotation of flange member 2, transmission member l8 and barrel member I8. This rotation causes the flange l6 to thread itself on the screw shaft 9, thus drawing the pinion 8 into engagement with the engine gear I, at which time the end 23 of the screw shaft engages the thrust washer 24 as shown in Fig. 3. Further rotation of the power shaft causes torque to be yieldingly transmitted to the pinion 8, such transmission being cushioned by the stretching and the torsional resilience of the transmission member I9. I

When the engine starts, the overrunning of the pinion and screw shaft member 8 causes it to thread itself back to its idle position,'running out of the threads l8 in the flange l8 and thereafter rotating idly until its momentum is dissipated. Reentry of the screw shaft 9 into the threads l8 upon reactuation of the starter drive may be assured by assembling the parts with the transmission member I8 under a slight degree of compression when the threads of the screw shaft 9 are withdrawn from the flange |8 of the barrel member. If preferred, a remeshing spring |3 may be interposed between the pinion 8 and the stop member l2 as illustrated in Fig. 3.

In the embodiment of the invention illustrated in Fig. 4, the pinion is arranged to travel away from the yieldable coupling when moving into engagement with the engine member instead of toward said coupling as in the embodiment first described.

In Fig. 4 a power shaft 3| has fixed thereon a drive member 32 by suitable means such as a pin 33, and a pinion member 34 is slidably journalled on the power shaft for movement into and out of engagement with a member such as a flywheel gear 35 of an engine to be started. Pinion 34 has a tubular threaded extension 38 suitably fixed thereto as by welding as indicated at 31, and a screw shaft 38 is slidably joumalled on the power shaft 3| in threaded engagement therewith.

A barrel member 39 is arranged to surround the threaded members and the drive member 32 and is fixedly connected to the drive member 32 for rotation therewith as by means of radial lugs 4| of the drive member fitting within notches 42 in the end of the barrel and retained therein by suitable means such as a split ring 43.

A flange member 44 is rigidly mounted in the opposite end of the barrel by means of radial 5 lugs 48 seated in notches 48 in the barrel and retained therein by means of a lock ring 41. A flange member 48 is rigidly connected to the screw shaft 38 as by welding as indicated at 48, and a yielding transmission element 8| of elas- 1 tically deformable material is suitably bonded as indicated at 52 and 88 to the flanges 44 and 48 respectively to form a yielding driving connection therebetween.

The idle position of the pinion 34 is defined 18 by its abutment with the end 54 of the screw shaft, in which position it is normally maintained by an anti-drift spring 88. The operative position of the pinion is defined by a stop member 88 located on the power shaft 8| by 20 means of a thrust ring 51 seated in a groove 88 in the shaft.

In the operation of this embodiment of the invention, rotation of the power shaft 8| is transmitted through the drive member 32, bar- 25 re] 33, flange member 44, transmission member 5| and flange member 48 to the screw shaft 38. The pinion. 34 is thereupon projected toward the flywheel gear 38 by the cooperation of its the torsional elasticity of the transmission member. Stretching of the transmission member is limited by engagement of the end of the screw shaft 38 and flange member 48 with a thrust washer 58 seated against the driving member 32, after which engagement the operation of the drive is cushioned further by the torsional elasticity of the transmission member.

In the embodiment of the invention illustrated in Figs. 8, 7 and 8 the drive is arranged so that when in idle position, the pinion is completely housed within the drive, so as to make a very short compact form of drive.

As illustrated in Fig. 6 a power shaft 8| has fixed thereon a driving member 82 as by means of a pin 83. A pinion 84 is slidably journalled on the power shaft for movement into and out of engagement with an engine flywheel gear 85, 85 and has a screw shaft 88 rigidly fixed thereto as by welding at 61.

A barrel member 88 is arranged to enclose the parts of the drive, and is rigidly connected to the drive member 82 by means of a disc 89 welded to the driving member as indicated at H and having radial lugs 12 extending into notches 13 in the end of the barrel and held therein by means of a lock ring 14.

A flange member 15 is rigidly fixed in the 65 other end of the barrel as by means of radial lugs 18 seated in notches l1 and maintained therein by means of a lockring iii. A hollow threaded sleeve 19 is mounted on the screw shaft 88 and has a flange member 8| fixed thereto as by welding as indicated at 82. Flange members I5 and 8| are yieldingly connected by means of a transmission member 83 of elastically deformable material bonded as indicated at 84 and 85 to the flanges 15 and 8| respectively.

The threaded sleeve i9 is preferably provided with a smooth counterbored portion 86 permitting the screw shaft to run off the ends of the threads in the sleeve when the pinion overruns the drive. A reentry spring 8! is provided for maintaining initial engagement of the threads of the screw shaft with the threads of the sleeve, and an anti-drift spring 88 is provided for yieldingly maintaining the pinion in its idle position.

In this embodiment of the invention, the operative position of the pinion is defined by'the abutment of the forward end 9| of the screw shaft against the flange member 15.

In operation, rotation of the power shaft 6| is transmitted through drive member 62, disc 69, barrel 68, flange member 15, transmission member 83 and flange 8| to the threaded sleeve '19. The pinion 64 and screw shaft 66 are thus caused to be threaded out of the barrel into engagement with the engine gear 65 until the end of the screw shaft abuts the flange member 15. Rotation is thereupon transmitted to the pinion yieldingly by virtue of the stretching and torsional elasticity of the transmission member 83. The stretching of the transmission member is limited by engagement of the flange 8| with a thrust washer 92 seated against the disc 69 of the driving member.

When the engine starts, overrunning of the pinion causes it to be threaded back into the sleeve 19 until the screw shaft 66 runs off the ends of the threads in the sleeve. The pinion and screw shaft can then overrun freely until their momentum is dissipated, after which initial engagement of the threads is effected by the reentry spring 81, the parts being maintained in their idle positions as illustrated by the antidrift spring 88.

Although certain embodiments of the invention have been shown and described in detail, it will be understood that other embodiments are possible and various changes may be made in the arrangements and proportions of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is:

1. In an engine starter drive, a power shaft, an engine driving member slidably journalled thereon, and means responsive to acceleration of the power shaft for moving the engine driving member into operative position including a flange member having an inclined connection with the engine driving member, a member rigidly connected to the shaft in advance of the flange member in the direction of travel of the engine driving member toward operative position, a block of elastically deformable material bonded at its ends to the flange member and the rigidly connected member respectively, and thereby forming a tensile connection therebetween, and stop means independent of the flange member for defining the operative position of the engine driving member and cooperating with the inclined connection of the engine driving member to cause the driving torque to stretch the elastic block and thereby form a yielding driving connection.

2. In an engine starter drive, a power shaft, an engine driving member slidably journalled thereon, and means "responsive to acceleration of the power shaft for moving the engine driving member into operative position including a flange member having a threaded connection with the engine driving member, a second flange member rigidly connected to the shaft in advance of the threaded flange member in the direction of travel of the engine driving member into operative position, a block of elastically deformable material bonded at its ends to said flange members and thereby completing a tensile connection between the power shaft and engine driving member, and stop means independent of the first-mentioned flange member, engageable by the engine driving member when in driving position.

3. In an engine starter drive, a power shaft, a driving member fixed thereon, a pinion member slidably journalled on the power shaft, a flange member, an elastic member attached at its ends to the driving member and flange member, said flange member having a threaded connection with the pinion member operative upon acceleration of the power shaft to draw the pinion into mesh with a member of an engine to be started, said pinion being arranged to run out of the threads in the flange member when the pinion member overruns the drive, and means whereby said overrunning action causes a slight compression of the elastic member, causing it to ensure reengagement of the threads of the flange and pinion members upon reactuation of the drive.

4. In an engine starter drive, a power shaft, a driving member fixed thereon, a pinion member slidably journalled on the power shaft, a flange member, a cylindrical block of elastically deformable material attached at its ends to the driving member and flange member and forming the sole operative connection therebetween, said flange member having a threaded connection with the pinion member operative upon acceleration of the power shaft to draw the pinion into mesh with a member of an engine to be started, said meshing action being cushioned by the stretching of the elastically deformable block, said pinion being arranged to run out of the threads in the flange member when the pinion member overruns the drive, and an abutment on the power shaft so defining the idle position of the pinion that said overrunning action causes a slight compression of the elastic block, causing it to ensure reengagement of the threads of the flange and pinion members upon reactuation of the drive.

EVERETT E. BALDWIN. 

